The invention relates to a hydrodynamic torque convertor with a bridging coupling.
Known from DE-A-3614158 is a torque convertor comprising a substantially pot-shaped housing which is adapted to be driven at the bottom end and which is at the opposite end connected to a pump wheel. A turbine wheel is disposed between the bottom and the pump wheel and is mounted on a gear shaft through a hub. A bridging coupling is disposed between the turbine wheel and the bottom of the housing and comprises the piston which can be applied against the inside face of the bottom and which forms a friction surface therewith. In the applied state, the piston transmits the torque from the housing to the gear shaft through a torsion spring arrangement.
For damping torsion vibrations in the bridged condition the known torque converter comprises a torsion spring arrangement and possibly friction means. This balancing out of torsion vibrations from the internal combustion engine extends downwards substantially to rotary speeds of 1700 . . . 1900 rpm. Since internal combustion engines are increasingly available whose full torque potential extends downwards as far as substantially lower rotary speeds, it must be ensured that adequate balancing-out also takes place in this lower speed range.